Hot Tub Forum
Original => Hot Tub Forum => Topic started by: jdotfite on June 26, 2010, 10:34:14 am
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I decided to try and build my own hot tub a few weeks ago and I just finished framing everything out. I am at the point now where I need to order my jets and get my plumbing done. I will be using a 1hp pump to power the jets. The tub is small (~150 gallons) so I won't need a ton of jets. I just can't seem to find any specific information on the web about which jets and how many would work well with "x"hp pump (in my case a 1hp). I can't even come up with a good guess. I know some jets use more power than others too.
I am really hoping someone here on the forum has the experience to help me out. I am excited to finish this project, I just don't want to order a bunch of stuff I can't use.
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I ordered a few random jet bodies and one jet from an ebay seller. I received them saturday. The jet bodies were a lot larger than I expected. The jet I bought didn't fit any of the bodies I ordered. I am thinking I may be better off buying complete jets from somewhere like spadepot.com. I wrote them an email Tuesday of last week and they still haven't responded. Not sure if I really want to order from them.
I am thinking of going with 4 jets to go with the 1hp pump. Pump should be here this week. Should I try testing it out and trying to figure out how many gpm it pumps? Maybe I can find out what the gpm some of spadepots jets pump out? I don't know how else to match them up.
Again, any help is appreciated.
Thanks guys,
Justin
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The pump should have a flow chart specifying the GPM for a given head. By calculating the head (length of pipe, loss from fittings, filter, heater etc.) you can determine the flow rate at the jets. Jets are rated at a required GMP
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There are many variables! As Dr. Spa has mentioned, jets are rated at a given flow. If you provide them with the appropriate flow rate, they will draw in air, mix it and give you a good massage. If you under or over feed them they will not - plus you may get pressure backing up and causing problems with plumbing by vibrating, making noise, or even loading the pump incorrectly.
A rule of thumb that I have used is to allow one fourth of a HP for each jet, but I used to install jets with removable orifices so I could 'tune' things after the fact. I don't know if they even offer jets like that anymore! Now they have removable nozzles of a variety of designs from straight to eyeball to spinners, you name it! You can find flow charts for most pumps at the manufacturer's web site, and just about all jets should be listed right next to specs which include the size of whole you need to drill, the size of plumbing you need to use, and the suggested flow.
Some Jets now have built-in valves, which is cool because if you don't want to do your homework you can simply pop in six or eight of those, and adjust the flow as you enjoy the tub by simply shutting off or turning on jets until it feels the way you like it - effectively going from a low-pressure (all jets running) to a real pounding (only one or two jets running). If you find that the best mix is to have four jets on, then you still get to chose which four jets you enjoy, and of course that can change from soak to soak, and from minute to minute as you move about from seat to seat.